(PTSA or HCl) for the amidation of methyl-pyroglutamate derivatives was investigated. In this study of the synthesis of P2X7 receptor (P2X7R) antagonists, ZrCl4 was the best catalyst for the synthesis of pyroglutamides substituted in position 1. Four new pyroglutamides have shown good antagonistic properties on the human P2X7 receptor (h-P2X7R).